Straightening brush



FIG. 1 is a front perspective view of a straightening brush embodying our design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a right-side elevation view thereof;

FIG. 4 is a left-side elevation view thereof;

FIG. 5 is a front elevation view thereof;

FIG. 6 is a rear elevation view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines illustrate portions of the straightening brush and form no part of the claimed subject matter. 

CLAIM The ornamental design for a straightening brush, as shown and described. 